Cash, cash equivalents and current marketable securities - Cash and Cash Equivalent Composition (Details) - USD ($) $ in Millions	Dec. 31, 2023	Jan. 01, 2023
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Fair value, available-for-sale	$ 8,874	$ 10,487
Cash & Cash Equivalents	21,859	12,889
Current Marketable Securities	1,068	9,392
Held-to-maturity Securities
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Carrying Amount, held-to-maturity	14,053	11,794
Held-to-maturity, unrecognized loss	0	(1)
Fair value, held-to-maturity	14,053	11,793
Cash & Cash Equivalents	13,556	10,921
Current Marketable Securities	497	873
Held-to-maturity Securities | Non-U.S. Sovereign Securities
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Carrying Amount, held-to-maturity	522
Held-to-maturity, unrecognized loss	0
Fair value, held-to-maturity	522
Cash & Cash Equivalents	174
Current Marketable Securities	348
Held-to-maturity Securities | Cash
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Carrying Amount, held-to-maturity	3,340	3,691
Held-to-maturity, unrecognized loss	0	0
Fair value, held-to-maturity	3,340	3,691
Cash & Cash Equivalents	3,340	3,691
Current Marketable Securities	0	0
Held-to-maturity Securities | U.S. Reverse repurchase agreements
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Carrying Amount, held-to-maturity	4,377	1,419
Held-to-maturity, unrecognized loss	0	0
Fair value, held-to-maturity	4,377	1,419
Cash & Cash Equivalents	4,377	1,419
Current Marketable Securities	0	0
Held-to-maturity Securities | Corporate debt securities
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Carrying Amount, held-to-maturity	338	873
Held-to-maturity, unrecognized loss	0	(1)
Fair value, held-to-maturity	338	872
Cash & Cash Equivalents	189	0
Current Marketable Securities	149	873
Held-to-maturity Securities | Money market funds
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Carrying Amount, held-to-maturity	4,814	5,368
Held-to-maturity, unrecognized loss	0	0
Fair value, held-to-maturity	4,814	5,368
Cash & Cash Equivalents	4,814	5,368
Current Marketable Securities	0	0
Held-to-maturity Securities | Time deposits
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Carrying Amount, held-to-maturity	662	443
Held-to-maturity, unrecognized loss	0	0
Fair value, held-to-maturity	662	443
Cash & Cash Equivalents	662	443
Current Marketable Securities	0	0
Available-for-sale Securities
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Carrying Amount, available-for-sale	8,875	10,521
Available-for-sale, unrecognized loss	(1)	(34)
Fair value, available-for-sale	8,874	10,487
Cash & Cash Equivalents	8,303	1,968
Current Marketable Securities	571	8,519
Available-for-sale Securities | Corporate debt securities
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Carrying Amount, available-for-sale	237	352
Available-for-sale, unrecognized loss	0	(1)
Fair value, available-for-sale	237	351
Cash & Cash Equivalents	43	46
Current Marketable Securities	194	305
Available-for-sale Securities | U.S. Gov't Securities
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Carrying Amount, available-for-sale	8,562	9,959
Available-for-sale, unrecognized loss	0	(28)
Fair value, available-for-sale	8,562	9,931
Cash & Cash Equivalents	8,259	1,922
Current Marketable Securities	303	8,009
Available-for-sale Securities | U.S. Gov't Agencies
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Carrying Amount, available-for-sale	71	210
Available-for-sale, unrecognized loss	(1)	(5)
Fair value, available-for-sale	70	205
Cash & Cash Equivalents	0	0
Current Marketable Securities	70	$ 205
Available-for-sale Securities | Other Sovereign Securities
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Carrying Amount, available-for-sale	5
Available-for-sale, unrecognized loss	0
Fair value, available-for-sale	5
Cash & Cash Equivalents	1
Current Marketable Securities	$ 4